A molded article that is excellent in corrosion resistance and abrasion resistance, suitable for dyeing and coloring and has good appearance and decorativeness may be attained by performing an alumite treatment on a molding made from an aluminum alloy.
A die-casting process used to fabricate precision castings by injecting a molten metal into a mold is known as one of the methods of molding an aluminum alloy because the die-casting process is appropriate for mass production at a relatively low cost and can fabricate moldings with complicated shapes which are hardly achieved through a pressing process.
Desirably, an aluminum alloy used in a die-casting process may have such characteristics that there is no hot-tearing during die casting, and the aluminum alloy has excellent filling property and is not adhered to a mold (that is, has excellent die-castability).
In the related art, ADC6 (Al—Mg based alloy), ADC (Al—Si—Cu based alloy) or the like, which provides high productivity and has a hardness required for processing, has been developed as an aluminum alloy having excellent die-castability. However, these alloys are excellent in die-castability but it is difficult to obtain a molded article with excellent sheen through an alumite treatment of the obtained molding.
Patent Document 1 discloses a high-pressure casting aluminum alloy providing a uniform oxide film without a color spot. This alloy is advantageous in that it has excellent die-castability and a molded article with high hardness can be obtained, whereas the molded article does not have good sheen.
Therefore, it has been expected that a novel aluminum alloy for die casting which is applicable to the fabrication of a molded article having high hardness and excellent sheen will be developed.
Patent Document 1: Japanese Patent Application Laid-Open No. 52-133012